1. Field of the Invention
The present invention relates to a structure with fine grooves such as a stamper for optical disc, an optical disc, a video disc, a CD, a DRAW (direct read after write) disc, a EDRAW (erasable direct read after write) disc, a disc media, an optical element, gratings, a photonic crystal and so on, a method for forming fine grooves and a method for forming a stamper producing the structure with fine grooves.
The present invention is applicable to a semiconductor process and production of a transistor, a memory and so on.
2. Description of Prior Art
Generally, to form a fine pattern, there has been taken a method for shortening wave length of an exposed light source, for example, using KrF, ArF and VUV (vacuum ultraviolet) and simultaneously for performing a high numerical aperture of an optical system. Further, a method of using EUV (soft X ray) and EB (electron beam) is also considered.
In Japanese Patent Laid-Open Publication No. Hei 5-3191, it is utilized that a wall surface of a structure is thickened in appearance by depositing silicon nitride on poly-silicon which is patterned, and therefore the poly-silicon is used for forming a fine pattern.
In Japanese Patent Laid-Open Publication No. Hei 8-288499, thin lines are formed by oxidization of poly-silicon.
However, there is a limitation to perform miniaturization of the pattern by merely shortening a wavelength of exposed light of KrF, ArF and so on.
Further, in aforementioned methods, there is a problem that a high-degree consideration is required to fixtures and fittings such as exposure in vacuum and so on and an expensive device is required.
Furthermore, in Japanese Patent Laid-Open Publication No. Hei 5-3191, there is a problem that it is necessary to form a thick silicon-nitride layer and thus it is difficult to form stably a pattern in order of Å since precision of the pattern is harmed.
Further, in Japanese Patent Laid-Open Publication No. Hei 8-288499, although thin lines are formed by oxidization of poly-silicon, since it is an object thereof to form quantal fine lines and a wet etching is used to patternize a poly-silicon layer, it is not possible to obtain high density of disc land & grooves. There is also a problem that since a basic layer is formed from the silicon layer, a step occurs between under layers of the poly-silicon and the exposed silicon layer.